This document is related to a touch sensitive screen interface. In particular embodiments, this document describes an intrinsically safe touch screen interface that can be used in process equipment environments.
Touch sensitive screens are used to control many electrical and mechanical devices. However, in industrial applications where explosive gasses or dusts may be present, touch screen interfaces have not been suitable for process equipment control because of the potential that the spark generated by the interface could create a hazardous condition. In hazardous environments, controllers have been limited to traditional metal covered keypads, explosion proof sealed mechanical switches, pneumatically purged membrane switches and similar devices, all of which keep the electrical hazard away from the explosive gas or dust.
With the advent of touch screen technology in cell phones, laptops, global positioning system (GPS) devices, and many other consumer and non-hazardous area industrial devices, it is desirable to develop a touch screen device that can be used with hazardous area process equipment or otherwise within such hazardous areas. Such a touch screen device can be considered intrinsically safe (IS) for this application. This document describes a touch-screen device that is directed to some or all of the problems listed above.